The present invention relates to a fishing rod having a solid rod section.
Japanese Utility Model Application Publication No. 59-20057 discloses a structure in which a so-called solid member, which is formed solidly by impregnating reinforced fibers arranged in the axial direction with a resin, is used at a tip of a fishing rod. This tip rod section is constructed such that glass fibers with a small modulus of elasticity are used as reinforced fibers of the solid member, and that a prepreg using carbon fibers with a large modulus of elasticity is wound around an outer periphery of a butt portion of the solid member and is formed integrally therewith. It has been the conventional practice to use a solid member as a tip rod section in this manner.
However, as rods for fishing large fish or fish with strong tugs, rod portions ranging from at least a butt rod to a rod portion close to a tip are conventionally formed from hollow rod pipes. The reason for this is that, since a large bending force acts in a butt portion when such fish are caught, the fishing rod must be made capable of withstanding the tugs of the fish by enlarging the bending rigidity of the butt portion to some degree, i.e., by enlarging the diameter to some degree, and that light weight must also be attained. However, the tip of the rod must naturally be made slender. Accordingly, hollow rod pipes which are each manufactured by winding a prepreg around a core are used as rod portions excluding at least a rod portion close to the tip, and these rod portions are generally joined such that they become gradually slender toward the tip, thereby forming a fishing rod of a predetermined length.
However, since the butt portion is formed from a hollow pipe whose bending rigidity is large to some extent and whose diameter is large, if this portion is deflected substantially, the so-called crush breakage occurs. For this reason, the portion close to an angler's hand is structured to be provided with even larger bending rigidity so that the portion close to the hand will not be deflected much. Since the fishing rod thus structured has a large diameter at the butt portion, and a predetermined small diameter at the tip portion, it is natural that, in general, the fishing rod becomes long. For this reason, in terms of the deflected state of the fishing rod in a case where a fish is caught, the fishing rod is deflected substantially from the intermediate portion to the tip, but is not deflected so much from the intermediate portion to the butt portion. Due to the distance from the butt portion to the intermediate portion, even in the state in which a fish is caught and the fishing rod is deflected, the distance from the butt portion being gripped by the angler to the rod tip is long, so that the bending moment acting in the butt portion due to the load of the fish and the like is very large, and the emaciation of the physical strength of the angler who withstands this bending moment is very intense.
In addition, since the carbon fibers wound around the outer periphery of the solid member disclosed in the above-described publication has a modulus of elasticity larger than that of the glass fibers of the solid member, the rigidity of the tip before and behind the position of a front edge of the wound prepreg changes sharply, and the state of deflection before and behind this position changes sharply. Hence, there is a drawback in that the fishing rod is liable to break at this position. In addition, since the kinds of reinforced fibers differ between the solid member and the prepreg wound therearound, the different coefficients of expansions are likely to distort the formed tip.